1. Technical Field
According to an exemplary embodiment of the present invention, there is provided a method of operating a datagram network node having at least one input channel and a plurality of output channels, said method comprising the steps of:
2. Related Art
It is now common for messages (whether they be telephone conversations or data file transfers) to be divided into packets before transmission across a communications network. This is advantageous to the operator of the communications network because packets from one message can be interspersed with packets from another message. That enables a more efficient utilisation of the available network resources.
Some packet networks offer the user a connectionless service. This means that a user using the network to transfer packets cannot rely on the network to output the packets in the same order he or she puts them in. In applications such as data transfer between two computers, the burden this places on the user is found to be acceptable. This is because computers are often supplied with networking software which controls the computer to attach a sequence number to each outgoing packet when it acts as a sender and to order received packets in accordance with their sequence number when it acts as a receiver.
Other packet networks offer the user a connection-oriented service. Here, the network can be relied on to output the packets derived from a given message in the same order as that in which they are supplied to the network. In practice, in order to offer such a service it is found necessary to send every one of the packets derived from a given message along the same route. Most telecommunications networks provide a connection-oriented service and this requirement for persistent routes reduces a telecommunications network operator's ability to manage the traffic traversing its network. Over recent years, computer data has provided an increasing proportion of telecommunications traffic. As explained above, data transfer between computers does not require a connection-oriented service—hence a telecommunications network that can take advantage of this and offer a connection-oriented service only to those that require it is becoming increasingly desirable.